Method and apparatus for managing disc defects using updateable DMA, and disc thereof

ABSTRACT

A disc defect management method and apparatus using a defect management area that can be updated, and a write once disc incorporating the method. A data area is disposed between a lead-in area and a lead-out area. The disc includes a defect management area (DMA) that is present in at least one of the lead-in area or the lead-out area, wherein defect information and defect management information are repeatedly recorded in the DMA according to a recording operation. Accordingly, the disc defect management method and apparatus enable effective use of the defect management area. The method is also applicable to a multi layer disc having a user data area on each layer. The defect information and the defect management information for an individual defect may include cumulative defect information and defect management information related to previously identified defects.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Patent Cooperation TreatyApplication No. PCT/KR2003/002121 filed Oct. 14, 2003 in the KoreanIntellectual Property Office, which claims priority to Korean PatentApplication Nos. 2002-63851 filed on Oct. 18, 2002, and 2002-79754 filedon Dec. 13, 2002 in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to disc defect management, and moreparticularly, to a method of and an apparatus for managing disc defectsusing a defect management area (DMA) that can be updated, and a disctherefor.

2. Description of the Related Art_Defect management is a process ofrewriting data stored in a user data area of a disc in which a defectexists. The data is rewritten to a new portion of the disc's data area,thereby compensating for the data loss caused by the defect. In general,defect management is performed using linear replacement or slippingreplacement. In linear replacement, the user data area in which a defectexists is replaced with a spare data area having no defects. In slippingreplacement, the user data area with the defect is marked, and datarecording is slipped to a next user data area having no defects.

Both linear replacement and slipping replacement are applicable only todiscs such as a DVD-RAM/RW, on which data can be repeatedly recorded andrecording can be performed using a random access method. In other words,linear replacement and slipping replacement are difficult to apply towrite once discs on which recording is allowed only once. In general,the presence of defects in a disc is detected by recording data on thedisc and confirming whether or not data has been recorded correctly onthe disc. However, once data is recorded on a write once disc, it isimpossible to overwrite new data and manage defects therein.

After the development of CD-R and DVD-R, a high-density write once discwith a recording capacity of several dozen GBs was introduced. This typeof disc can be used as a backup disc, since it is not expensive andallows random access that enables fast reading operations. However,defect management is not available for write once discs. Therefore, abackup operation is discontinued when a defective area, i.e., an areawhere a defect exists, is detected during the backup operation. Ingeneral, a backup operation is performed when a system is not frequentlyused, e.g., at night when a system manager does not operate the system.In this case, it is more likely that a discontinued backup operationwill not be completed where a defective area of a write once disc isdetected.

SUMMARY OF THE INVENTION

The present invention provides a method of defect management and anapparatus that can be applied to write once discs, and a write oncedisc.

The present invention also provides a defect management method andapparatus that can manage disc defects even when a defect is detectedduring a recording operation, enabling the recording operation tocontinue without interruption, and a write once disc adapted to use thedefect management method.

According to an aspect of the present invention, there is provided awrite once disc having a single record layer in which a lead-in area, adata area, and a lead-out area are sequentially disposed, the disccomprising a defect management area (DMA) that is present in at leastone of the lead-in area or the lead-out area, wherein defect informationand defect management information are repeatedly recorded in the DMAaccording to a recording operation.

According to an aspect of the present invention, there is provided adouble record layer write once disc having a first record layer in whicha lead-in area, a data area, and an outer area are sequentially locatedand a second record layer in which an outer area, a data area, and alead-out area are sequentially located, the disc comprising a DMA thatis present in at least one of the lead-in area, the lead-out area, orthe outer area, wherein defect information and defect managementinformation are repeatedly recorded in the DMA according to a recordingoperation.

The defect information and the defect management information may becontinuously updated and recorded until the DMA has no room forrecording.

The addresses of data and replacement data, which are most recentlyrecorded in user areas and spare areas of the record layers,respectively, may be recorded in the DMA. Also, a pointer pointing out aposition of the defect information may be recorded in the DMA. Thedefect management information corresponding to the defect information,which is recorded per recording operation, may be recorded in the DMA.

The defect information may include state information regarding a defect,a pointer pointing out the position of the defect, and a pointerpointing out a position of replacement for the defect.

The state information may indicate whether the defect is a continuousdefect block or a single defect block. The state information may specifythat the defect is a continuous defect block, and corresponding pointersfor the defect and the replacement may point out a start of the defectand a start of the replacement, respectively, or specify that the defectis a continuous defect block, and corresponding pointers for the defectand the replacement may point out an end of the defect and an end of thereplacement, respectively.

According to an aspect of the present invention, there is provided amethod of managing disc defects in a disc, comprising recording defectinformation regarding data, which is recorded in a data area of the discaccording to a first recording operation, as a plurality of first defectinformation in a DMA that is present i in at least one of a lead-in areaor a lead-out area of the disc; recording management information formanaging the first defect information as first defect managementinformation in the DMA; and repeating recording of the first defectinformation and recording of the first defect management information atleast once while increasing indexes given to the recording operation,defect information, and defect management information by 1.

The repeating recording of the first defect information and recording ofthe first defect management information may be performed until the DMAhas no room for recording.

During the recording of the first defect information, the defectinformation may be sequentially recorded in a defect information areaincluded in the DMA, starting from the start of the defect informationarea toward its end, and during the recording of the first defectmanagement information, the defect management information maysequentially recorded in a defect information management area includedin the DMA, starting from the start of the defect information managementarea toward an end of the defect information management area.Alternatively, during the recording of the first defect information, thedefect information may be sequentially recorded in the defectinformation area included in the DMA, starting from the end of thedefect information area toward its start, and during the recording ofthe first defect management information, the defect managementinformation may be sequentially recorded in the defect informationmanagement area included in the DMA, starting from the end of the defectinformation management area toward the start of the defect informationmanagement area. Alternatively, during the recording of the first defectinformation and the recording of the first defect managementinformation, the corresponding defect information and defect managementinformation may be sequentially recorded to form a pair in the defectmanagement area, starting from the start of the defect management area,and during the recording of the first defect information and therecording of the first defect management information, the correspondingdefect information and defect management information may be sequentiallyrecorded to form a pair in the defect management area, starting from theend of the defect management area.

The recording of the first defect information may comprise recordingdata in predetermined units; verifying the recorded data to detect anarea of the disc with a defect; storing information, which designatesthe area with the defect as a defective area, and information, whichdesignates a replacement area that is replacement for the defectivearea, as the first defect information in memory; repeating recording ofdata, verifying the recorded data, and storing of the first defectinformation at least once; and reading the first defect information fromthe memory and recording the read information as the first defectinformation in the DMA.

A replacement area for the defective area is allotted to a spare area ofthe disc.

According to an aspect of the present invention, there is provided arecording apparatus comprising a recording/reading unit that recordsdata on or reads data from a disc; and a controller that controls therecording/reading unit to repeatedly record defect information regardingdata, which is recorded in a data area of the disc per recordingoperation, as defect information in a DMA that is present in at leastone of a lead-in area or a lead-out area of the disc, and recordmanagement information for managing the defect information as defectmanagement information in the DMA.

The controller may control the recording/reading unit to record thedefect information and defect management information per recordingoperation in the DMA until the DMA has no room for recording, andinforms a user that disc defect management cannot be further performedwhen the DMA has no room for recording.

According to an aspect of the present invention, there is provided arecording apparatus comprising a recording/reading unit that recordsdata on or reads data from a disc; and a controller that controls therecording/reading unit to record defect information regarding data,which is recorded in a data area of the disc according to a firstrecording operation, as a plurality of first defect information in a DMAthat is present in at least one of a lead-in area or a lead-out area ofthe disc, record management information for managing the first defectinformation as first defect management information in the DMA, recorddefect information regarding data, which is recorded in the data areaaccording to a second recording operation, as a plurality of seconddefect information in the DMA, and record management information formanaging the second defect information as second defect managementinformation in the DMA.

The controller may control the recording/reading unit to record data inthe data area while increasing indexes given to the recording operation,defect information, and defect management information by 1, until theDMA has no room for recording, and informs a user that disc defectmanagement cannot be further performed when the DMA has no room forrecording.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram of a recording apparatus according to anembodiment of the present invention;

FIGS. 2A and 2B illustrate structures of a disc according to embodimentsof the present invention;

FIG. 3A illustrates data structures of the disc of FIGS. 2A and 2Baccording to an embodiment of the present invention;

FIG. 3B illustrates an example of a disc with the defect managementareas shown in FIG. 3A;

FIGS. 4A through 4D illustrate data structures of a defect managementarea (DMA) according to embodiments of the present invention;

FIGS. 5A and 5B illustrate data structures of defect managementinformation DDS #i according to embodiments of the present invention;

FIG. 6 illustrates a data structure of defect information DFL #iaccording to an embodiment of the present invention;

FIG. 7 is a diagram for explaining recording of data in a user data areaA and a spare area B, according to an embodiment of the presentinvention;

FIG. 8 is a diagram illustrating effective use of a data area accordingto the present invention;

FIGS. 9A and 9B illustrate data structures of defect information DFL #1and DFL #2 recorded according to the recording of data shown in FIG. 7;

FIG. 10 illustrates a data structure of information regarding defect #i;

FIG. 11 is a flowchart illustrating a defect management method accordingto an embodiment of the present invention; and

FIG. 12 is a flowchart illustrating a defect management method accordingto another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

FIG. 1 is a block diagram of a recording apparatus according to anembodiment of the present invention. Referring to FIG. 1, the recordingapparatus includes a recording/reading unit 1, a controller 2, and amemory 3. The recording/reading unit 1 records data on a disc 100, whichis an information storage medium according to an embodiment of thepresent invention, and reads back the data from the disc 100 to verifythe accuracy of the recorded data. The controller 2 performs defectmanagement according to the present invention. In the embodiment shownin FIG. 1, the controller 2 uses a verify-after-write method in whichdata is recorded on a disc in predetermined units of data and theaccuracy of the recorded data is verified to detect a defect in thedata. In other words, the controller 2 records user data on the disc 100in units of recording operations and verifies the recorded user data todetect an area of the disc 100 in which a defect exists. Thereafter, thecontroller 2 creates information that indicates a position of the areahaving the defect and stores the created information in the memory 3.Every time that such information is created, the controller 2 stores thecreated information in the memory 3. If the amount of the storedinformation reaches to a predetermined level, the controller 2 recordsthe stored information as defect information on the disc 100.

Here, the recording operation is a unit of work determined according toa user's intention or is a recording work to be performed. According tothis embodiment, a recording operation indicates a process in which thedisc 100 is loaded into the recording apparatus, data is recorded on thedisc 100, and the disc 100 is taken out from the recording apparatus.During the recording operation, data is recorded and verified at leastonce. In general, data is recorded and verified several times. Defectinformation, which is obtained using the verify-after-write method, istemporarily stored in the memory 3.

When a user presses the eject button (not shown) of the recordingapparatus in order to remove the disc 100 after recording of data, thecontroller 2 expects the recording operation to be terminated. Next, thecontroller 2 reads the information from the memory 3, provides the readinformation to the recording/reading unit 1, and controls therecording/reading unit 1 to record it on the disc 100.

The recording/reading unit 1 records the information provided from thecontroller 2 as defect information in a defect management area of thedisc 100 and further records management information, which is used tomanage the defect information, in the defect management area.

FIGS. 2A and 2B illustrate structures of the disc 100 of FIG. 1according to embodiments of the present invention. FIG. 2A illustratesin detail a single record layer disc representation of disc 100 having arecord layer L0. The disc 100 includes a lead-in area, a data area, anda lead-out area. The lead-in area is located in an inner part of thedisc 100 and the lead-out area is located in an outer part of the disc100. The data area is present between the lead-in area and the lead-outarea, and divided into a user data area and a spare area.

The user data area is an area where user data is recorded, and the sparearea is the replacement area for a user data area having a defect,serving to compensate for loss in the recording area due to the defect.On the assumption that defects may occur within the disc 100, the sparearea may be about 5% of the entire data capacity of the disc 100, sothat a greater amount of data can be recorded on the disc 100.

FIG. 2B illustrates a double record layer embodiment of the disc 100having two record layers L0 and L1. A lead-in area, a data area, and anouter area are sequentially formed from an inner part of the firstrecord layer L0 to an outer part of the first recording layer. Also, anouter area, a data area, and a lead-out area are sequentially formedfrom an outer part of the second record layer L1 to an inner part of thesecond recording layer. Unlike the single record layer disc of FIG. 2A,the lead-out area is present in the inner part of the disc 100 of FIG.2B. That is, the disc 100 of FIG. 2B has an opposite track path (OTP) inwhich data is recorded starting from the lead-in area of the firstrecord layer L0 toward the outer area and continuing from the outer areaof the second record layer L1 to the lead-out area at the inner part ofthe second recording layer. A respective spare area is allotted to eachof the record layers L0 and L1.

In the embodiment shown in FIG. 2B, the spare areas are present betweenthe user data area and the lead-out area in the recording layer L1 andbetween the user data area and the outer area in the recording layer L1.If necessary, a portion of each user data area may be used as anotherspare area, that is, one or more additional spare areas may be presentbetween the lead-in area and the lead-out area.

FIG. 3A illustrates details the disc 100 according to an embodiment ofthe present invention. Referring to FIG. 3A, if the disc 100 is a singlerecord layer disc as shown in FIG. 2 a, a defect management area (DMA)is present in at least one of the lead-in area or the lead-out area. Ifthe disc 100 is a double record layer disc as shown in FIG. 2B, the DMAmay be present in at least one of the lead-in area, the lead-out area,or the outer area. In the case of the double record layer disc shown inFIG. 2B, the DMA may be formed in at least one of the lead-in area orthe lead-out area, which are located in the inner part of the disc 100.

In general, information that relates to managing defects in the disc 100is recorded in the DMA. Such information includes the structure of thedisc 100 for defect management, the position of defect information,whether defect management is performed or not, and the position and sizeof a spare area. In the case of a write once disc, new data is recordedafter previously recorded data when the previously recorded datachanges.

In general, when a disc is loaded into a recording/reading apparatus,the apparatus reads data from a lead-in area and a lead-out area of thedisc to determine how to manage the disc and record data on or read datafrom the disc. However, if the amount of data recorded in the lead-inarea/lead-out area increases, a longer time is spent on preparing therecording or reproducing of data after the loading of the disc. To solvethis problem, a DMA is determined to be an area in which recordedinformation can be updated in this embodiment. That is, defectinformation and defect management information are updated and recordedin the DMA during every recording operation. Updating defect managementinformation and defect information reduces the amount of informationthat the recording/reading unit requires for a recording/reproducingoperation.

Since defect management is performed using linear replacement, thedefect information includes information indicating the position of anarea of the disc 100 having a defect and information indicating theposition of an area of the disc 100 that is replacement for the areahaving the defect. More preferably, the defect management informationfurther includes information indicating whether the area having thedefect is a single defect block, or a continuous defect block in whichphysically continuous defects exist. The defect management informationis used to manage the defect information and includes informationindicating the point of the disc 100 where the defect information isrecorded. More specifically, the defect management information furtherincludes information indicating the position of user data that is mostrecently recorded in the user data area and a replacement area that ismost recently formed in a spare area. Detailed data structures of defectinformation and defect management information are explained below.

The defect information and defect management information are recordedevery time when a recording operation ends. In the DMA, informationregarding a defect occurring in data recorded during a first recordingoperation and information regarding a replacement area are recorded asdefect information #1, and information regarding a defect occurring indata recorded during a second recording operation and informationregarding a replacement area are recorded as defect information #2.Further, information for managing defect information #1 and #2 isrecorded as defect management information #1 and #2, respectively, inthe DMA. That is, generally, defect information #i may be used inassociation with a defect #i.

In the embodiment shown in FIG. 3A, defect information #i furthercontains previously recorded defect information #1, #2, #3, . . . and#i-1, in addition to defect information #i. Therefore, arecording/reading unit can easily obtain defect information just byreading the most recently recorded temporary defect information #i anddefect management information #i from the DMA.

In the case of a high-density disc with a recording capacity of severaldozen GBs, it is desirable that a cluster is allocated to an area inwhich defect management information #i is recorded and four—eightclusters are allocated to an area in which defect information #i isrecorded. This is because it is preferable to record new information inunits of clusters to update information when a minimum physical unit ofrecord is a cluster, although the amount of defect information #i isjust several KBs. A total amount of defects allowed in a disc ispreferably about 5 percent of the disc recording capacity. For instance,about four—eight clusters are required to record defect information #i,considering that information regarding a defect is about 8 bytes longand the size of a cluster is 64 KB.

The verify-after-write method may be performed on defect information #iand defect management information #i. When a defect is detected,information recorded in an area of a disc having a defect may be eitherrecorded in a spare area using linear replacement, or recorded in anarea adjacent to the area having the defect using slipping replacement.

FIG. 3B illustrates an example of a disc with the defect managementareas (DMAs) of FIG. 3A. If a disc is a single record layer disc asshown in FIG. 2A, the DMA is present in at least one of the lead-in areaor the lead-out area of the disc. If the disc is a double record layerdisc as shown in FIG. 2B, the DMA is present in at least one of thelead-in area, the lead-out area, or the outer area of the disc.Preferably, DMAs are present in the lead-in area and the lead-out area.

Referring to FIG. 3B, two DMAs are formed to increase the robustness ofdefect management information and defect information. In detail, a testarea is an area that is used to measure recording conditions of data. Adrive and disc information area contains information regarding a driveused during recording and/or reproducing operations and disc informationindicating whether the disc is a single record layer disc or a doublerecord layer disc. A first buffer area, a second buffer area, and athird buffer area act as buffers, i.e., they become borders between theother areas.

FIGS. 4A through 4D illustrate data structures of a DMA according toembodiments of the present invention.

Referring to FIG. 4A, a DMA is logically divided into a defectinformation area DFL and a defect management information area DDS. Inthe defect information area DFL, defect information lists DFL #1, DFL#2, DFL #3, . . . are sequentially recorded starting from the start ofthe defect information area DFL toward the end thereof. The defectinformation lists DFL #1, DFL #2, DFL #3, . . . are repeatedly recordedseveral times to increase the robustness of information. For example, asshown in FIG. 4A, the defect information DFL #2 is recorded P times(first copy through pth copy). Also, in the defect managementinformation area DDS, defect management information DDS #1, DDS #2, DDS#3, . . . are sequentially recorded starting from the start of thedefect management information area DDS. The defect managementinformation DDS #1, DDS #2, and DDS #3 correspond to defect informationlists DFL #1, DFL #2, and DFL #3, respectively.

Referring to FIG. 4B, a DMA is logically divided into a defectinformation area DFL, and a defect management information area DDS, butthe sequences of recording information are not the same as the sequencesshown in FIG. 4A. More specifically, in the defect information DFL shownin FIG. 4B, defect information DFL #1, DFL #2, DFL #3, . . . aresequentially recorded starting from an end of the defect informationarea toward a start of the defect information area. In the defectmanagement information area DDS, defect management information DDS #1,DDS #2, DDS #3, . . . are sequentially recorded starting from an end ofthe defect management information area DDS. Here, the defect managementinformation DDS #1, DDS #2, and DDS #3 correspond to the defectinformation DFL #1, DFL #2, and DFL #3, respectively. Similarly, thedefect information DFL #1, DFL #2, DFL #3, . . . are each recordedseveral times to increase the robustness of information. Referring toFIG. 4B, the defect information DFL #2 is recorded P times.

Referring to FIG. 4C, corresponding defect information and defectmanagement information are recorded to form pairs in a DMA. In the DMA,management information DMA #1, DMA #2, DMA #3, . . . are sequentiallyrecorded starting from the start of the DMA. The management informationDMA #1 contains a pair of defect management DDS #1 and defectinformation DFL #1, management information DMA #2 contains a pair ofdefect management information DDS #2 and defect information DFL #2, andDMA #3 contains a pair of defect management information DDS #3 anddefect information DFL #3. Likewise, the defect information DFL #1, DFL#2, and DFL #3, . . . are repeatedly recorded several times to increasethe robustness of information. FIG. 4C illustrates repetitive recordingof the defect information DFL #1 P times.

Referring to FIG. 4D, corresponding defect information and defectmanagement information are recorded to make pairs in a DMA but thesequence of recording the information is not the same as shown in FIG.4C. More specifically, in the DMA shown in FIG. 4D, managementinformation DMA #1, DMA #2, DMA #3, . . . are sequentially recordedstarting from the end of the DMA. The management information DMA #1contains a pair of defect management information DDS #1 and defectinformation DFL #1, the management information DMA #2 contains a pair ofdefect management information DDS #2 and defect information DFL #2, themanagement information DMA #3 contains a pair of defect managementinformation DDS #3 and defect information DFL #3. Similarly, the defectinformation DFL #1, DFL #2, DFL #3, . . . are repeatedly recordedseveral times to increase the robustness of information. In particular,FIG. 4D illustrates repetitive recording of the defect information DFL#1 P times.

FIG. 5A illustrates a data structure of defect management informationDDS #i recorded on a single record layer disc. Referring to FIG. 5A, thedefect management information DDS #i contains an identifier for the DDS#i and information indicating a position of corresponding defectinformation DFL #i (DFL # i pointer). As previously mentioned related toFIGS. 4A through 4D, the defect information DFL #i according to thepresent invention is repeatedly recorded several times, and therefore,the information indicating the position of the defect information DFL #iincludes pointers that point out the positions of the repeatedlyrecorded defect information DFL #i. Referring to FIG. 5A, since thedefect information DFL #i is recorded P times, the defect managementinformation DDS #i includes P pointers pointing out the positions of thedefect information DFL #i.

Further, the defect management information DDS #i, which is recorded ina single record layer disc, contains the address of a record layer L0,which is most recently recorded in a user data area, and the address ofreplacement data for the record layer L0, which is most recentlyrecorded in a spare area. In this way, a reproducing apparatus caneasily reproduce the disc just by referring to the most recentlyrecorded information. A detailed description thereof will be describedbelow.

FIG. 5B illustrates a data structure of defect management informationDDS #i recorded on a double record layer disc. The defect managementinformation DDS #i includes an identifier thereof and informationregarding the position of corresponding defect information DFL #i. Aspreviously mentioned with reference to FIGS. 4A through 4D, the defectinformation DFL #i according to the present invention is repeatedlyrecorded several times, and therefore, the information regarding theposition of the defect information DFL #i contains pointers pointing outthe positions of the repeatedly recorded defect information DFL #i. Asshown in FIG. 5B, since the defect information DFL #i is recorded Ptimes, P pointers are included in the defect management information DDS#i.

Also, the defect management information DDS #i, which is recorded in adouble record layer disc, contains the address of a first record layerL0, which is most recently recorded in a user data area, the address ofreplacement for the first record layer L0, which is most recentlyrecorded in a spare area, the address of a second record layer L1, whichis most recently recorded in the user data area, and the address ofreplacement for the second record layer L1, which is most recentlyrecorded in the spare area. In this way, a reproducing apparatus caneasily reproduce the disc just by referring to the most recentlyrecorded information. A detailed description thereof will be describedbelow.

FIG. 6 illustrates a data structure of defect information DFL #i.Referring to FIG. 6B, defect information DFL #i contains an identifierthereof, and information regarding defect #1, defect #2, . . . , anddefect #K (K is an integer). Each of the information regarding defect#1, defect #2, . . . , and defect #K provides state informationindicating the position of the defect, the position of replacement forthe defect, and whether an area having the defect is a single defectblock or a continuous defect block. A detailed description of the datastructure will be described below.

FIG. 7 illustrates recording of data in a user data area A and a sparearea B according to an embodiment of the present invention.

Data can be processed in units of sectors or clusters. A sector denotesa minimum unit of data that can be managed in a file system of acomputer or in an application, and a cluster denotes a minimum unit ofdata that can be physically recorded on a disc at once. In general, oneor more sectors constitute a cluster.

There are two types of sectors: a physical sector and a logical sector.The physical sector is an area on a disc where a sector of data is to berecorded. An address for detecting the physical sector is called aphysical sector number (PSN). The logical sector is a unit in which datacan be managed in a file system or an application. An address fordetecting the logical sector is called a logical sector number (LSN). Adisc recording/reading apparatus detects the recording position of datausing a PSN. When recording data on a disc, the entire data is managedin units of LSNs in a computer or in an application and the position ofdata is detected using an LSN. The relationship between an LSN and a PSNis changed by a controller of the recording/reading apparatus, based onwhether the disc contains a defect and an initial position of recordingdata.

Referring to FIG. 7, A denotes a user data area and B denotes a sparearea in which PSNs are allocated to a plurality of sectors (not shown)in ascending order. In general, each LSN corresponds to at least onePSN. However, since LSNs are allocated to non-defective areas, includingreplacement areas of the spare area B, in ascending order, thecorrespondence between the PSNs and the LSNs is not maintained when adisc has a defective area, even if the size of a physical sector is thesame as that of a logical sector.

In the data area A, sections 71 through 77 denote predetermined units ofdata in which the verify-after-write method is performed. A recordingapparatus records user data in the section 71, returns to the start ofthe section 71, and checks if the user data is appropriately recorded ora defect exists in the section 71. If a defect is detected in a portionof the section 71, the portion is designated as defect #1. The user datarecorded in the defect #1 is also rewritten to a portion of the sparearea B. Here, the portion of the spare area B in which data recorded inthe defect #1 is rewritten is called replacement #1. Next, the recordingapparatus records user data in section 72, returns to the start of thesection 72, and checks whether the data is properly recorded or a defectexists in the section 72. If a defect is detected in a portion of thesection 72, the portion is designated as defect #2. Likewise, areplacement #2 corresponding to the defect #2 is formed in the sparearea B. Further, defect #3 and replacement #3 are designated in section73 of the user data area A and the spare area B, respectively. Insection 74, a defect does not exist and a defective area is notdesignated.

The recording apparatus records information regarding the defects #1,#2, and #3 designated in the sections 71 through 74 as a defectinformation list DFL #1 in the DMA when recording operation #1 isexpected to end, after recording and verifying to the section 74, i.e.,when a user presses the eject button of a recording apparatus orrecording of user data allocated in a recording operation is complete.Also, defect management information for managing the defect informationlist DFL #1 is recorded as defect management information DDS #1 in theDMA.

When a second recording operation starts, data is recorded in sections75 through 77, and defects #4 and #5 and replacements #4 and #5 areformed in the user data area A and the spare area B in the DMA,respectively, as performed in the section 71. Defect #5 is a continuousdefect block in which defects occur continuously, whereas the defects#1, #2, #3, and #4 are single defect blocks, each block in which adefect occurs. The replacement #5 is a continuous replacement block thatis the replacement for the defect #5. Here, a block refers to a physicalor logical unit of data in which data is recorded. If the secondrecording operation is expected to end, the recording apparatus recordsinformation regarding the defects #4 and #5 as defect information DFL#2, and records the information contained in the defect information DFL#1 once again. Thereafter, defect management information for managingthe defect information DFL #2 is recorded in the DMA.

FIG. 8 is a diagram illustrating effective use of a data area accordingto an embodiment of the present invention. Referring to FIG. 8, it iseasy to detect an available portion of the data area, using the addressof user data that is most recently recorded in a user data area and theaddress of data in a spare area that is a replacement for a defect. Inparticular, the available portion can be more easily detected, when theuser data is recorded from the inner part or outer part of the user dataarea to the outer part or inner part, respectively, and the data, whichis replacement for the detect, is recorded from the outer part or innerpart of the spare area to the inner part or outer part, respectively. Inother word, the user data and the data for replacement are preferablyrecorded in an opposite recording direction.

The data, which is most recently recorded in the user data areas ofrecord layers L0 and L1, has a physical address with the largest numberwhen physical addresses of user data are increased from the inner partof the record layer L0 to the outer part and increased from the outerpart of the record layer L1 to the inner part. In contrast, the mostrecently recorded replacement has a physical address with the smallestnumber when physical addresses of replacements are reduced from theouter part to the inner part in a spare area of the record layer L0 andincreased from the inner part to the outer part in a spare area of therecord layer L1.

Accordingly, as previously mentioned, if the addresses of the mostrecently recorded data and replacement are included in defect managementinformation DDS #i, it is possible to detect the positions of data andreplacement to be newly recorded without completely reading defectinformation DFL #i and calculating the positions of defects. Further,available portions of the user data area and the spare area are locatedphysically and continuously, thereby enabling effective use of the userarea.

FIG. 9 illustrates data structures of defect information DFL #1 and DFL#2 recorded as explained with respect to FIG. 7. FIG. 10 illustrates adata structure of information regarding defect #i recorded as explainedwith reference to FIG. 7.

Referring to FIG. 9, the defect information DFL #1 contains informationregarding defects #1, #2, and #3. The information regarding defect #1indicates the position of an area in which defect #1 exists and theposition of an area in which replacement #1 is recorded. The informationregarding defect #1 may further include information indicating whetherdefect #1 is a continuous defect block or a single defect block.Likewise, the information regarding defect #2 indicates whether defect#2 is a continuous defect block or a single defect block, the positionof an area in which defect #2 exists. and the position of an area inwhich replacement #2 is recorded. The information regarding defect #3indicates whether defect #3 is a continuous defect block or a singledefect block, the position of an area in which defect #3 exists, and theposition of an area in which replacement #3 is recorded.

The defect information DFL #2 further contains information regardingdefects #4 and #5 in addition to the information contained in the defectinformation DFL #1. That is, the defect information DFL #2 includes theinformation regarding defect #1, the information regarding defect #2,the information regarding defect #3, the information regarding defect#4, and the information regarding defect #5.

Referring to FIG. 10, the information regarding defect #i includes stateinformation indicating whether defect #i is a continuous defect block ora single defect block, a pointer pointing out defect #i, and a pointerpointing out replacement #i. If the state information indicates thatdefect #i is a continuous defect block, the state information describeswhether the pointer for defect #i points out the start of the continuousdefect block or the end thereof and whether the pointer for replacement#i points out the start of the continuous defect block or the endthereof. If the state information describes the pointer for defect #i asthe start of the continuous defect block, the pointer for defect #i is astarting physical sector number (PSN) of the continuous defect block andthe pointer for replacement #i is a starting PSN of replacement #i. Onthe contrary, when the state information describes the pointer fordefect #i as the end of the continuous defect block, the pointer fordefect #i is an ending physical sector number (PSN) of the continuousdefect block and the pointer for replacement #i is an ending PSN ofreplacement #i. The definition of a continuous defect block using stateinformation enables effective recording of information and savesrecording space, although information regarding defects is recorded inunits of blocks.

The pointer for defect #i specifies a starting and/or an ending point ofdefect #i. For instance, the pointer for defect #i may include astarting PSN of defect #i. The pointer for replacement #i specifies astarting and/or ending points of replacement #i. For example, thepointer for replacement #i may include a starting PSN of replacement #i.

Hereinafter, a disc defect management method according to an embodimentof the present invention will be described with reference to theaccompanying drawings.

FIG. 11 is a flowchart illustrating a disc defect management methodaccording to an embodiment of the present invention. Referring to FIG.11, in action 1101, a recording apparatus records defect informationregarding data recorded according to a first recording operation asdefect information #1 in a DMA, so as to manage disc defects. In action1102, management information for managing defect information #1 isrecorded as defect management information #1 in the DMA.

In action 1103, whether a vacancy is present in the DMA is checked. Ifit is determined in action 1103 that the vacancy is present, actions1101 and 1102 are repeated while indexes given to a recording operation,defect information, and defect management information are increased by1, in action 1104. However, if it is determined in action 1103 that thevacancy is not present, a user is informed that disc defect managementcannot be further performed in action 1105.

FIG. 12 is a flowchart illustrating a disc defect management methodaccording to another embodiment of the present invention. Referring toFIG. 12, user data is recorded in a data area of a disc in units of datato facilitate the verify-after-write method in action 1201. In action1202, the data recorded in action 1201 is verified to detect an area ofthe disc having the defect. In action 1203, the controller 2 of FIG. 1designates the area having the defect as a defective area, controls therecording/reading unit 1 to rewrite data recorded in the defective areato a spare area so as to create a replacement area, and creates pointerinformation that points out the positions of the defective area and thereplacement area. In action 1204, the pointer information is stored asdefect information #1. In action 1205, it is checked whether the firstrecording operation is expected to end. If it is determined in action1205 that the first recording operation is not expected to end, actions1201 through 1204 are repeated.

In action 1206, if it is determined in action 1205 that the firstrecording operation is likely to end, i.e., when the recording of theuser data is complete by user input or according to the first recordingoperation, the stored defect information #1 is read and recorded asdefect information DFL #1 in the DMA. In action 1207, managementinformation for managing the defect information DFL #1 is recorded asdefect management information DDS #1 in the DMA. In action 1208, whethera vacancy is present in the DMA is checked. If it is determined inaction 1208 that the vacancy is present, actions 1201 through 1207 arerepeated while increasing indexes given to a recording operation, defectinformation DFL, defect management information DDS by 1, in action 1209.If it is determined in action 1208 that the vacancy is not present, auser is informed that disc defect management cannot be further performedin action 1210.

As described above, the present invention provides a disc defectmanagement method that is applicable to write once discs. According tothe present invention, disc defect management is performed such thatdefect information and management information for managing the same areupdated and recorded in a defect management area (DMA), thereby enablingeffective use of the DMA. Accordingly, user data is recorded even onwrite once discs while managing disc defects therein, thereby performingbackup operations more stably without interruptions.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A write once disc having at least one record layer in which a lead-inarea, and a data area are disposed, the disc comprising a defectmanagement area (DMA) that is present in the lead-in area, whereindefect information and defect management information are repeatedlyrecorded in the DMA.
 2. The disc of claim 1, wherein a plurality of theDMAs are present.
 3. The disc of claim 1, wherein: the data areacomprises a user data area and a spare area; and an address of data thatis most recently recorded in the user area of the record layer and anaddress of replacement data that is most recently recorded in the sparearea of the record layer are recorded in the DMA.
 4. The disc of claim1, wherein a pointer pointing out a position of the defect informationis recorded in the DMA.
 5. The disc of claim 1, wherein the defectinformation for a defect contains state information specifying a stateof the defect, a pointer pointing out a position of the defect, and apointer pointing out a position of a replacement for the defect.
 6. Thedisc of claim 5, wherein the state information indicates whether thedefect is a continuous defect block or a single defect block.
 7. Thedisc of claim 5, wherein: the state information indicates that thedefect is a continuous defect block, and corresponding pointers for thedefect and the replacement point out a start of the defect and a startof the replacement, respectively.
 8. The disc of claim 5, wherein: thestate information indicates that the defect is a continuous defectblock, and corresponding pointers for the defect and the replacementpoint out an end of the defect and an end of the replacement,respectively.
 9. A recording apparatus comprising: a recording/readingunit that records data on or reads data from a disc; and a controllerthat controls the recording/reading unit to repeatedly record defectinformation regarding data, which is recorded in a data area of thedisc, as defect information in a defect management area (DMA) that ispresent at least one of a lead-in area or a lead-out area of the disc,and to repeatedly record management information for managing the defectinformation as defect management information in the DMA.